In the drop down menu on the top left corner, select iOS, tvOS, watchOS if it's not already selected,
then navigate to Identifiers > App IDs.

Click the + button to create a new App ID.

To create the new App ID:

Input a Name for your App ID (e.g. Firebase Sample App)

Input a Team ID. This value must match the Team ID in the Membership tab.

In the App ID Suffix section, select Explicit App ID, then input your
Bundle ID (e.g. com.google.samples.firebaseexample). The value of the Bundle ID
should match the value that you are using in your app's Info.plist and the value
that you are using to get a configuration for FCM.

In the App Services section, make sure that Push Notifications is checked.

Click Continue and check that your input is correct:

The value of Identifier should match the concatenation of the values of
the Team ID and of the Bundle ID

Push Notifications should be Configurable

Click Register to create the App ID.

Create the Provisioning Profile

To test your app while under development, you need a Provisioning Profile for development
to authorize your devices to run an app that is not yet published on the App Store.